1. Field of the Invention
The present invention relates to a stator assembly of a torque converter used with an automatic transmission of a vehicle and the like. More specifically, the present invention relates to a stator assembly for a torque converter, which is supported by needle bearings in an axial direction.
2. Related Background Art
FIG. 17 is an axial sectional view of a conventional stator assembly into which needle bearings are incorporated. On the other hand, FIG. 18 is a front view of the stator assembly, looked at from a direction shown by the arrow VIX, shoving that a race of the needle bearing is fitted in a side portion of a bush in the conventional assembly.
In FIG. 17, a stator assembly 150 comprises a vane wheel 160 and an outer race 168 of a one-way clutch 170 is fitted into an inner periphery of the vane wheel 160. The one-way clutch 170 is a one-way clutch of sprag type and includes an outer race 168, an inner race 162 disposed within the outer race 168 in a concentric relationship thereto, sprags 163 disposed between the outer race 168 and the inner race 162 and adapted to transmit torque, holders 164 for holding the sprags, and ribbon springs 165 for applying cocking moment to the respective sprags to engage them with the outer and inner races.
On axial both ends of the inner race 162 and the outer race 168, there are provided bushes 161, 172 for maintaining both races in the concentric relationship and for preventing the holders 164 and the ribbon springs 165 from dislodging in the axial direction. The bushes 161, 172 are axially stationary with respect to the vane wheel 160 by means of snap rings 166, 167, respectively.
Races 174, 171 of needle bearings 173, 169 are fitted in stepped portions formed on the bushes 161, 172 axially outwardly. The races 174, 171 are provided with annular extensions that are fitted in stepped portions formed on the bushes or the inner periphery of the vane wheel. As shown in FIG. 18, four extensions disposed along the circumferential direction are fitted in the respective stepped portions of the bush.
In the above-mentioned conventional stator assembly, since axial movements of the races of the needle bearings are not restricted, there arises a problem that the needle bearings may be dislodged during conveyance and transportation.